Group

Our journal article entitled “Modelling of beam-driven Alfvén modes in TJ-II plasmas” has been accepted for publication in Nuclear Fusion. Nuclear Fusion is one of the renowned journals in our field.

The paper reports on our modelling results aimed at understanding a certain type of energetic-particle-driven instabilities called Alfvén modes in TJ-II stellarator plasmas and their comparisons with experimental results. In particular, we have modelled Alfvén eigenmodes in TJ-II discharges with a dynamically changing magnetic configuration when both steady and chirping modes are observed. The modelled mode frequencies and radial locations are found to be consistent with the experimental findings. We also have drawn important conclusions on the properties of the energetic particles that are resonant with the modes.

This week, WPCD developers from all around EUROfusion countries have met at Innsbruck, Austria, in the last WPCD code camp of 2018. 37 participants have been working on various activities, all of them aligned towards the European integrated modelling efforts. Discussions have been carried out in the integration of codes within the IMAS (Integrated Modelling & Analysis Suite) ant ITM aiming to bring together codes from fusion research centers.

The work was based on the research she has been carrying out since last March in our group and in close collaboration with the Materials group at the CASE department at BSC, under the supervision of Dr. Stephan Mohr and Prof. Dr. Mervi Mantsinen. The defense took place at the Faculty of Sciences of Universitat Autònoma de Barcelona, Spain, and was graded with a top mark, proving the relevance and originality of it.

The paper entitled “Modelling of JET hybrid plasmas with emphasis on performance of combined ICRF and NBI heating” has been published by Nuclear Fusion. It advances our understanding of the optimisation of fusion performance of the recent Joint European Torus (JET) hybrid plasmas. The hybrid scenario is an advanced regime of tokamak plasma operation expected to be applied in ITER. It is characterized by a low plasma current Ip which allows operation at a high normalised beta as well as a safety factor at the plasma centre greater than 1 which is beneficial from the plasma stability point of view.

The paper focuses on the impact of neutral beam injection (NBI) and specially ion cyclotron resonance frequency (ICRF) heating on the neutron production rate. The main scheme studied is minority hydrogen (H) in a deuterium (D) plasma with D beams. The modelling takes into account the synergy between ICRF and NBI heating through the second harmonic cyclotron resonance of D beam ions which allows us to assess its impact on the neutron rate RNT. Apart from the D scenario, the deuterium-tritium (DT) scenario is also assessed through an extrapolation of D high-performance hybrid discharges. These results are relevant for the forthcoming DTE2 campaign at JET where one of the goals is to achieve the highest possible fusion performance for a duration of more than 5 s.